Consolidated Statements Of Income - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
INTEREST INCOME
Interest and fees on loans		$ 1,036,491	$ 1,062,771	$ 984,397
Interest on loans held for sale		131	165	583
Interest on investment securities		310,181	271,774	278,755
Interest on federal funds sold		31	49	659
Interest on securities purchased under agreements to resell		33,090	13,358	13,649
Interest on deposits with banks		103,799	121,440	103,248
Total interest income		1,483,723	1,469,557	1,381,291
INTEREST EXPENSE
Savings, interest checking and money market		210,308	226,876	146,392
Certificates of deposit of less than $100,000		34,032	42,226	38,690
Certificates of deposit of $100,000 and over		52,086	67,060	61,057
Interest on federal funds purchased		5,518	12,221	25,265
Interest on securities sold under agreements to repurchase		69,884	80,908	73,164
Interest on other borrowings		37	20	38,594
Total interest expense		371,865	429,311	383,162
Net interest income		1,111,858	1,040,246	998,129
Provision for loan losses		56,138	32,903	35,451
Net interest income after provision for loan losses		1,055,720	1,007,343	962,678
NON-INTEREST INCOME
Trust fees		232,700	214,430	190,954
Bank card transaction fees		184,267	189,784	191,156
Deposit account charges and other fees		108,246	100,336	90,992
Consumer brokerage services		22,051	18,141	17,223
Capital market fees		20,655	19,776	14,100
Loan fees and sales		13,882	12,890	11,165
Other		70,480	60,196	57,455
Total non-interest income		652,281	615,553	573,045
INVESTMENT SECURITIES GAINS (LOSSES), NET
Investment securities gains (losses), net	[1]	3,660	7,823	14,985
NON-INTEREST EXPENSE
Salaries and employee benefits		628,453	607,862	584,063
Data processing and software		133,970	127,390	118,758
Net occupancy		54,320	53,223	53,629
Professional and other services		48,856	35,077	36,198
Marketing		24,688	22,353	24,511
Equipment		21,508	20,619	19,548
Supplies and communication		19,686	19,291	19,420
Deposit insurance		10,049	16,482	33,163
Other		38,296	48,932	41,692
Total non-interest expense		979,826	951,229	930,982
Income before income taxes		731,835	679,490	619,726
Less income taxes		161,136	145,089	134,549
Net income		570,699	534,401	485,177
Less non-controlling interest expense (income)		4,448	8,070	8,117
NET INCOME ATTRIBUTABLE TO COMMERCE BANCSHARES, INC.		$ 566,251	$ 526,331	$ 477,060
Net income per common share - basic (in dollars per share)		$ 4.04	$ 3.69	$ 3.30
Net income per common share - diluted (in dollars per share)		$ 4.04	$ 3.69	$ 3.30

[1] Available for sale debt securities, equity securities, and other securities.